Hoosier Crumb Cake

My husband and I live about 15 miles east of Indiana. I received this recipe about 40 years ago from a friend, but I'm not sure of its origins. Because of its name, I'm guessing it had its beginnings in the "Hoosier State".12-16 ServingsPrep: 15 min. Bake: 30 min.
Ingredients
- 1/2 cup butter, softened
- 2 cups packed brown sugar
- 2 cups all-purpose flour
- 1 egg, beaten
- 1 cup buttermilk
- 1 teaspoon vanilla extract
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- Whipped cream and fresh mint, optional
Directions
- In a bowl, cream the butter and brown sugar. Add flour; mix until
- blended. Set aside 1/2 cup for topping.
- To the remaining mixture, add the egg, buttermilk, vanilla, baking
- soda and salt; stir just until blended. Pour into a greased 13-in. x
- 9-in. baking pan. Sprinkle with the reserved flour mixture.
- Bake at 375° for 30-35 minutes or until a toothpick inserted near
- the center comes out clean. Cool on a wire rack. Garnish with
- whipped cream and mint if desired. Yield: 12-16 servings.
Nutrition Facts: 1 serving (1 piece) equals 222 calories, 6 g fat (4 g saturated fat), 29 mg cholesterol, 241 mg sodium, 39 g carbohydrate, trace fiber, 3 g protein.